Underreamer



- l v. P. SK|NNER.

UNDERREAMER.

Y Y APPLICATION FILEUAPRA I9, 1920.

Patentdne. 14,1920.

, UNITEDv sTA'Es PATENT ori-ucla.

CHARLES P. SKINNEB, OF ORCUTT, CALIFORNIA.

To all whom it may concern.'

Be it known that I, CHARLES P. SKINNER, a citizen of thefUnited States, residing at Orcutt, in the 'county of Santa Barbarajand State of California, have invented new and useful Improvements in Underreamers, of

A which the following is a specification.

This invention relates to underreamers, namely devices' for enlarging vwell holes so that the casing ma .be lowered in same as 'the development o the well hole proceeds.

In the standardform of drilling a ^recip rocating bit is operated in the formation of the well hole and this is lowered through the casing and only cuts or drills or bores a hole having a diameter substantially that of t'he inside of the well casing. ,It'therefore is necessary to ream or cut out the an nul'ar formation beneath' the casing, or the casing and'its shoe, in order to permit the casing to be further lowered. To do this underreamers are employed, and the same are used in substitution for the bit, and are re` cipocated by the beam at the mouth of the we f The present invention has for its object the provision of an improved underreamer which will be superior in point of relative simplicity and inexpensiveness of construction, taken in conjunction with positiveness in operation,`reliability and durability, facility in adjustment, safety in use, and which will be devoid of liability of the cutters and the attendant features being lost in the hole in case" 'of breakage therein or in the parts suspending or controlling same.

With the above and other objects in view,

'the invention consists in the novel an'd useful provision," formation, construction, 40\

combination, .association and relative arrangement of parts, members and features,

all as hereinafter described, .shown in the-- drawing, and finally pointed out in claims.

In the drawing:

Figure 1 is `a lvertical cential sectional View, partly in elevation and partly broken away, of 4an underreanier embodying the invention and shown in conjunction with a portion of well casing and the shoe thereof, the parts of the underreamer being shown in collapsed condition for passage through the cas'ing and its shoe;

Fig. 2 is a view similar to Fig. 1 showing the underreamer in expanded or operative condition;

Fig. 3 is a vertical sectional view, partly UNDERREAMER.

Specification of Letters Patent. Patented Dec. 14, 1920. Application led April 19, 1920'. SeraI No. 374,935. i

in elevation and partly broken away, taken on the line ac3-5U", Fig. 2, and looking'in the direction of the appended' arrows;

Fig. 4 is la transverse detail sectional view, taken upon the line m4-m1Fig. 2, and

`looking in the direction of the appended` Referring with particularity to the drawl ing, vA designates a portion of a length of well easing, with itsishoe B, within whicliis disposed the mandrel or tubular-body Cof an underreamer having at the lower end Athereof an open bowl mouth o with a prefably cylindrical internal bore, leadingV up to an annular shoulder 6 above which is pro'- vided a chamber 7 of lesser diameter than the bowl mouth o,- and within which is threaded, at the lower end, as at 8, a detachable hollow slotted extension 9 which may be prevented from turning by a lateral screw pin 9.n and through which .plays lengthwise a spring-actuated rod 10,' the coiled compression spring 11 of. which surrounds the rod, bearingat its lower end upon the top of the hollow slotted extension 9, and at its upper end beneath a bushing 12 slipped onto the upper end of the rod 10 and maintained in position of adjustment to vary the compression of the spring 1l by a nut 13 threaded to the upper end of the. rod

10. A transverse key '14 is inserted through commodates the reciprocating rod 10. This slot 17 extends from a shoulder 17 some what above the lower end of the hollow .slotted extension 9 upwardly toV a point somewhatI below the shoulder GQ- Tlie lower end of the extension, 17h` beneath theshoulder 17, is laterally extended or extended transversely of the mandrel C and its bowl e, and its ends are :notched to lit under the lower end of the ilo-wl .mouth c, as at 17C. The hollow slottedfcltension 9, in the slotted portiorgrl-N7athereof, above the transverse iin extension or partition 17h, tapers quite abruptly downwardlyto such partition 17h.' The partition 17 h acts as an expanding me1nber for the cutters D, and is provided at its lower portion with a wedge-shaped spreader 19, preferably integral with such partition 17h, providing opposed downwardly expanding surfaces 19a for the cutters, which at their upper endsmergeinto substantially parallel opposed inthrust surfaces 19h.

The shanks 16 of the cutters are prefer` partition 17D. The cutters are expanded by.

means of angularly directed inner faces 2O and 21 which are provided at their inner faces, and which cooperate with the 'wedge faces 19a, and finally with the parallel faces 19b on the expanding partition 17", bringing the inner faces 21 ultimately into iinal engagement with such .parallel opposed faces 19b when the cutters are in the finally expanded positions shown in Fig. 2. Riding shoulders 22 are' provided upon enlarged portions of the stock of the cutter bodies 28, beneath the shanks 16, and these coperate with the shoe B to cause the cutters to be drawn down over the expanding partition 17b and to collapse the same, bringing the inner faces 2O down beneath and slightly spaced froin'the'wedge faces 19, as shown in Fig. 1. The inner' faces 20 and21 are formed at the lower portions of the shanks 16 where they merge into the stock of -the `cutter bodies 23. These riding shoulders 22 merge into upthrust shoulders 24 which engage the lower periphery of the bowl mouth c when the cutters 'are expanded, 'imparting upthrust in reaming to the mandrel C. The inthrust in reaming is transmitted by the faces 20 to the parallel faces 19", and any outthrust, as above pointed out, is taken care of by the inner faces 16b of the enlarged cutter shank portions 16a.

These latter enlarged portions 1Ga are pro'- vided with lower terminal shoulders 16c which are adapted to catch 'upon the wedge partition 17h in case'the keylf parts or the rod 10 breaks, thus preventing the loss of the 'cutters in the hole and perhaps avoiding an expensive and elaborate fishing job. It will be understood that the spring 11 exerts a tendentv to maintain the cutters. D in expanded positions, and that as soon as' the cutters pass the shoe they will automatically expand into 'the reaming or expanded positions shown in Fig. 2.`

The cutter bodies 23are providedfat their lower ends and at their outer edges with cutting edges 25, and-the cutters may be dressed out and repaired as required when the same become worn, or ready replacements may be made, the same being capable of assembling,

together with the spring-actuated rod andA other parts, at the lower end of'the bowl mouth c.

The'cutters, due to the particular arrange' ment and accommodation of features of the re'amer, may be made very wide, with plenty of stock to dress-out, the inthrust is well taken care of and rotatory action prevented by the wedging partition 17h, and the cut- 'ters may execute a wide out in each stroke,

thus tending to the fast making of hole It will be seen that the key 14C takes into eyes laJL in the cutter shanks 16, which eyes are slightly .enlarged to permit the cutters to tilt or teeter upon such key.

It is obvious'that many changes and variations may be made in practising the invention, in departing from the showing of the accompanying drawing and the foregoing description, without departing from the true spirit. of the invention.

Having thus disclosed my invention, I claim and desire to secure by Letters Patent:

1. In an underreamer, the combination with a body having an open mouth at the lower end thereof, of a slotted extension arranged ywithin the mouth and provided with an expansion head, cutters provided with.

Shanks which project into the open mouth,

said shanks being formed 4with shoulder por-` sion head, cutters provided with shanks.

which extend into the mouth of the body and also provided with shoulders adapted to cooperate with the expansion head, said shanks having portions adapted to engage the expanding head to prevent loss of the cutters, a spring actuated rod slidable within the hollow portion of the extension, and a key carried by the rod and operable within the slot of the extension, said key engaging the cutter shanks.

3. An underreamer including a body formed with a spring receiving chamber and having a month at the lower end thereof. a hollow slotted extension fitted in the lowes' end. of the spring receiving chainber and projecting Vinto the mouth, a substantially annular chamber being provided surrounding the extension and the extension having an expanding head, cutters provided with Shanks proj ectng into theannular chamber and constructed for coperation with the expanding head, the upper ends of the Shanks being curved to fit around the extension and being provided with shoul- V ders adapted to engage the expanding head to prevent loss of the cutters, a spring actulated rod sldable within the hollow exten-` name to this specification in the presence of` Witnesses.

two subscribin y v ARLES P. SKINNER.

Witnesses: j

J. H. HARTMAN,

L. J. MORRIS. y 

